1. Field of the Invention
This invention relates to communications devices that receive electronic communication transmissions and in particular to personal communications systems, processes and devices that minimize power consumption by adjusting amplifier linearity and dynamic range.
2. Related Art
Portable electronic devices have become part of many aspects of personal, business, and recreational activities and tasks. The popularity of various portable personal electronic communications systems, such as portable phones, portable televisions, and personal pagers, continues to increase. As the popularity of portable electronic systems has increased, so has the demand for smaller, lighter, and more power efficient devices.
Amplification of received electronic signals is a function performed in many portable electronic systems. Amplification circuitry tend to dissipate significant amounts of power and generate significant amounts of heat. It is common practice to design the Radio Frequency (RF) amplification portion of receiver circuitry within portable electronic communication devices to worse case, or one amplifier fits all, signal environment design standards. These standards dictate that the xe2x80x9cfront endxe2x80x9d RF amplifier be designed as a compromise between maximum amplification, and preserving linearity of nearby transmissions that are being received.
Designing receiver circuitry to worse case design standards is common for several reasons. First, receiver amplifiers are designed to worst case specifications because manufacturers generally want their receiving device to have the maximum range possible without distorting the received signal of a nearby transmission. If a portable communication device has a greater range than a competing model, a significant marketplace advantage is obtained. If the communications receiver distorts nearby transmissions, however, it may be perceived as being of inferior quality.
Traditionally, power savings in receiver design has received secondary emphasis in the design of portable electronics equipment. More design effort has been expended on the broadcast portions of portable communication devices because the broadcast portions of the electronics generally consume considerably more power than the receiver circuitry. Because of this higher power consumption, improving the power consumption of the broadcast may realize significant power savings. Conversely, the receiver circuitry consumes less power. Therefore, reducing the power requirements of the receiver results in less improvement. However, if RF amplifiers for the receiver circuitry could be designed to optimally amplify the signals within their bands, amplification of received signals could be accomplished more efficiently and performance improvements could be realized.
This invention addresses problems related to power consumption by dynamically adjusting the gain, range, and linearity of the receiving amplifier. The adjustment of the RF amplifier is based on the desired signal received and what portion of the overall signal the desired signal comprises. By optimally amplifying the desired signal received while minimizing power consumption, the optimal amplification is achieved.
A front end communication amplifier amplifies a band of radio signals that are received by an antenna. The amplified band of signals are then downconverted. The desired signal is extracted from the band of signals and amplified prior to demodulating and decoding the information in the signal. The circuits that amplify the RF Signal are commonly designed for worst case performance, so the RF amplifier stage is designed for maximum gain and maximum linearity, even though the signal being received may not require maximum gain or linearity. The RF amplifier commonly stays in a maximum gain, maximum linearity mode even though the signal being received could be better amplified by changing the parameters of the amplifier.
For example, it is desirable to amplify the signal intended to be received as much as possible in the front end, or RF amplification stages. Applying amplification at the front end is desirable because the farther down the amplification chain that a signal is amplified, generally the noisier the signal becomes. It is therefore usually advantageous to amplify a signal as much as possible in the front end of the amplification chain. Significant performance improvements of the receiving portion communications receiving devices are available if the parameters of the front end RF amplifier are tailored to the signal environment. Because of the performance improvement available there is a need for improved front end amplification control in communications receivers.
Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.